Two coins of diameter 2 𝑐𝑚 and 4 𝑐𝑚 respectively are kept one over the other as shown in the figure , find the area of the shaded region in 𝑠𝑞𝑢𝑎𝑟𝑒 𝑐𝑚.

We have been given the diameter of two coins as 2 𝑐𝑚 and 4 𝑐𝑚 respectively. We need to find the area of the shaded region.

𝑅𝑎𝑑𝑖𝑢𝑠 = $\frac{Diameter}{2}$ 

Thus, Radius of the two coins are 1 cm and  2cm, respectively.

Area of a circle (𝐴) with radius 𝑟 can be expressed as 𝐴 = πr² 

𝐴𝑟𝑒𝑎 𝑜𝑓 𝑡ℎ𝑒 𝑠ℎ𝑎𝑑𝑒𝑑 𝑟𝑒𝑔𝑖𝑜𝑛 = 𝐴𝑟𝑒𝑎 𝑜𝑓 𝑏𝑖𝑔𝑔𝑒𝑟 𝑐𝑜𝑖𝑛 − 𝐴𝑟𝑒𝑎 𝑜𝑓 𝑠𝑚𝑎𝑙𝑙𝑒𝑟 𝑐𝑜𝑖n

$\begin{array}{r}\Rightarrow \text{ Area }=\pi (2{)}^2-\pi (1{)}^2\\ \Rightarrow \text{ Area }=\pi (4-1)\text{ sq. cm }\\ \Rightarrow \text{ Area }=3\pi sq.\mathrm{cm}\end{array}$